Verclsid CLSID Execution

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects the potential abuse of the verclsid.exe utility to execute malicious files via generated CLSIDs. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns associated with verclsid.exe. This activity is significant because verclsid.exe is a legitimate Windows application used to verify CLSID COM objects, and its misuse can indicate an attempt to bypass security controls. If confirmed malicious, this technique could allow an attacker to execute arbitrary code, potentially leading to system compromise or further malicious activities.

name: Verclsid CLSID Execution
id: 61e9a56a-20fa-11ec-8ba3-acde48001122
version: 9
creation_date: '2021-09-29'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
description: The following analytic detects the potential abuse of the verclsid.exe utility to execute malicious files via generated CLSIDs. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line patterns associated with verclsid.exe. This activity is significant because verclsid.exe is a legitimate Windows application used to verify CLSID COM objects, and its misuse can indicate an attempt to bypass security controls. If confirmed malicious, this technique could allow an attacker to execute arbitrary code, potentially leading to system compromise or further malicious activities.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |
    | tstats `security_content_summariesonly` values(Processes.process) as process
    values(Processes.parent_process) as parent_process values(Processes.process_id)
    as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where
    (Processes.process_name="verclsid.exe" OR Processes.original_file_name="verclsid.exe")
    Processes.process="*/S*"
    Processes.process="*/C*"
    Processes.process="*{*"
    Processes.process="*}*"
    by Processes.action Processes.dest Processes.original_file_name
       Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
       Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
       Processes.process Processes.process_exec Processes.process_guid Processes.process_hash
       Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path
       Processes.user Processes.user_id Processes.vendor_product
    | `drop_dm_object_name(Processes)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `verclsid_clsid_execution_filter`
how_to_implement: The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
known_false_positives: windows can used this application for its normal COM object validation.
references:
    - https://gist.github.com/NickTyrer/0598b60112eaafe6d07789f7964290d5
    - https://bohops.com/2018/08/18/abusing-the-com-registry-structure-part-2-loading-techniques-for-evasion-and-persistence/
analytic_story:
    - Unusual Processes
asset_type: Endpoint
mitre_attack_id:
    - T1218.012
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.012/verclsid_exec/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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b74c4bf6-84c2-4376-ae0c-a89a6772b5c1

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

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Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

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